Metal fire

Threshold limit values for the components of cemented carbides and tool steels are given in Table 14 (176). There is generally no fire or explosion hazard involved with tool steels, cemented carbides, or other tool materials. Fires can be handled as metal fires, eg, with Type D fire extinguishers. Most constituents of tool materials do not polymerize. 

Occurrence. Carbon monoxide is a product of incomplete combustion and is not likely to result where a flame bums in an abundant air supply, yet may result when a flame touches a cooler surface than the ignition temperature of the gas. Gas or coal heaters in the home and gas space heaters in industry have been frequent sources of carbon monoxide poisoning when not provided with effective vents. Gas heaters, though properly adjusted when installed, may become hazardous sources of carbon monoxide if maintained improperly. Automobile exhaust gas is perhaps the most familiar source of carbon monoxide exposure. The manufacture and use of synthesis gas, calcium carbide manufacture, distillation of coal or wood, combustion operations, heat treatment of metals, fire fighting, mining, and cigarette smoking represent additional sources of carbon monoxide exposure (105—107). 

In addition to assessing a fire s flame cliaracteristies to detennine tlie cause and effect of a fire, knowledge of tlie fire accident type will provide insight into its ignition source and possible fire protection and prevention methods. Electrical, chemical, and metal fires can occur in a solid, liquid, or gaseous pliase. Section 7.3 presents a detmled discussion of tliese fires and tlieir ignition sources. 

As a result, sand was recommended for extinguishing fires involving metals. Nevertheless, sand should not be used for metal fires, especially alkali metal fires where the reaction is particularly violent. 

This reaction shows that it is impossible to put out lithium fires with sodium chloride although it is an extinguishing agent for metal fires. 

Methods of extinguishing different types of metal fires are reviewed, with 86... 

ALKALI-METAL ALLOYS, ALKALI METALS DEVARDA S ALLOY, FERROALLOY POWDERS FINELY DIVIDED METALS, LANTHANIDE METALS LIGHT ALLOYS, METAL DUSTS METAL FIRES, MILD STEEL... 

Perform a thorough safety and fire protection review including the prevention of and response to metal fires, pyrophorics, and catalysts. 

This event was categorized as a "metal fire" with the structured carbon steel packing acting as the fuel. This is not a generally recognized and understood mechanism and was not identified in the PFHA or FFHA. 

As a result of this investigation, all attempts should be made to remove the packing prior to performing hot work. If hot work is required, a thorough safety and fire protection review should be performed (including the prevention of and response to metal fires). 

Class D Fire in combustible metals Fires in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium. 

Primer A term for the device used to ignite smokeless powder in small arms ammunition. An impact-sensitive composition is used. When struck by a metal firing pin, a primer emits a burst of flame capable of igniting the propellant charge. Several typical primer mixtures are given in Table 6.2. 

In discussing the extinguishing of fires, Sax makes the following remarks about metal fires ... 

Pyrotechnic primer compositions are often used to ignite gun propellants. The primer emits a burst of flame when it is struck by a metal firing pin, igniting the gun propellant. These primer compositions are therefore very sensitive to initiation and are capable of generating heat and shock. In order to reduce the sensitivity during the manufacturing process, the composition is used in the paste form. Examples of pyrotechnic compositions used in primers are presented in Table 8.5. 

Caution. The residues on the glassware and the frit may contain sodium-potassium alloy and/or tris(trimethylsilyl)arsine and should not be exposed to air until disposal. tert-Butyl alcohol and isopropyl alcohol can be used to destroy these pyrophoric compounds however, this should be performed in a fume hood, as arsine gas may be generated. The solid on the frit can be mixed with class D metal fire extinguisher and subsequently treated with either of the aforementioned alcohols. 

Alkali metals (Na or K) and metallic hydrides, on contact with water, produce hydrogen and sufficient heat to ignite the gas with explosive rapidity. Waste scraps of sodium should be added in small proportions to a high-boiling alcohol, such as propanol or butanol, and safely disposed of after all action ceases. Nonaqueous fire extinguishers such as dry soda ash are the only kind that should be used on an alkali metal fire. See also Alkali and Alkaline Earth Metals, Vol 1, p A125-L... 

Metal cyanides(and cyano complexes), 216 Metal derivatives of organofluorine compounds, 217 IV-Metal derivatives, 218 Metal dusts, 220 Metal fires, 222 Metal fulminates, 222 Metal halides, 222 Metal—halocarbon incidents, 225 Metal halogenates, 226 Metal hydrazides, 226 Metal hydrides, 226 Metal hypochlorites, 228 Metallurgical sample preparation, 228 Metal nitrates, 229 Metal nitrites, 231 Metal nitrophenoxides, 232 Metal non-metallides, 232 Metal oxalates, 233 Metal oxides, 234 Metal oxohalogenates, 236 Metal oxometallates, 236 Metal oxonon-metallates, 237 Metal perchlorates, 238 Metal peroxides, 239 Metal peroxomolybdates, 240 Metal phosphinates, 240 Metal phosphorus trisulfides, 240 Metal picramates, 241 Metal pnictides, 241 Metal polyhalohalogenates, 241 Metal pyruvate nitrophenylhydrazones, 241 Metals, 242 Metal salicylates, 243 Metal salts, 243 Metal sulfates, 244 Metal sulfides, 244 Metal thiocyanates, 246 Metathesis reactions, 246 Microwave oven heating, 246 Mild steel, 247 Milk powder, 248... 

Bertelli, G. Costa, L. Fenza, S. Marchetti, E. Camino, G. Locatelli, R. Thermal behavior of bromine-metal fire retardant systems, Polymer Degradation and Stability, 1988, 20(3 1), 295-314. 

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